Recording from DVR to MBP

I am recording shows from my Scientific Atlanta (Cablevision) 8300HD DVR to my MBP using Elgato Video Capture. My problem is with audio. The volume on the recorded show on the Mac is extremely low. I called Cablevision to see if there is anyway to increase the output volume, they of course said no. And I did not find any settings to do so, so maybe they are right. My Visio VS42L does not have audio out, that I can figure.